The output power of a laser system is limited by thermal, nonlinear, and material effects. The effectiveness of lasers is largely determined by the brightness of the laser, coarsely defined as the ratio of the output power to the two-dimensional beam parameter product (i.e., the product of the beam area and the beam divergence). In order to overcome the output power limitation, simply adding laser beams together is insufficient to guarantee good beam quality. Typically, adding laser beams together will yield a spatially incoherent beam, which will result in reduced beam quality and a beam brightness that is, at best, equal to that of the individual beams, i.e. no brightness improvement. One skilled in the art recognizes that the term laser can comprise a laser oscillator, a laser amplifier, or a set of laser oscillators or amplifiers.